Outrunner Motors

What is an Outrunner Motor? 

An outrunner motor has a rotor rotate on the outside of a stator. 

Outrunner motors are commonly used in drones and hub motors because they offer several advantages over other types of motors. 

Custom Outrunner Motors

Get in touch with us to discuss more about custom outrunner motors. Innotec uses its existing frame sizes and also will build and design a unit based on your input requirements.  

Outrunner Motor Manufacturer

Innotec Power serves OEMs to customize and mass manufacture outrunner motors. Working with Innotec, gives OEMs the opportunity to change mechanical and electrical features of their motor specifications and find the right solution in a constraint driven environment. For drones, sizes can vary but Innotec specializes in large drone motors.

Advantages of Outrunners

Some of the main reasons why outrunner motors are used include:

1. High torque: Consider the the magnet area and diameter rotor to be the primary source of torque. For a given housing diameter constraint, you  can fit more surface area and a larger diameter as an outer rotor versus an inner rotor pmg. Therefore most outrunner motors have a higher torque-to-weight ratio than other types of motors, which means they can generate more power while remaining lightweight and compact. This is ideal for drones, which need to be lightweight to fly efficiently but also need to generate enough power to lift and move.
2. High power-to-weight ratio: Outrunner motors also have a high power-to-weight ratio, which means they can generate a lot of power for their size and weight. This is a result of the high torque for given size. 
3. High RPM: Outrunner motors are designed to run at high RPMs, which allows them to generate more power. For drones,  high RPMs are essential. An outer rotor allows higher speed possibilities.
4. Low noise: Outrunner motors tend to be quieter than other types of motors, which is important for drones as they are often used in urban areas or other areas where noise is a concern.
5. Durability: Outrunner motors are known to be durable and withstanding rigorous usage, which is important for drones that may be flown frequently or in harsh conditions.
6. Brushless: Outrunner motors are brushless, which means that they have a longer lifespan and are more efficient than brushed motors.

All of these factors make outrunner motors an ideal choice for drones. They are able to generate a lot of power while remaining lightweight and compact, and they are also durable, efficient, and quiet.

Outrunner vs Inrunner motor

To recap, an outrunner has the rotor on the outside and an inrunner (a more traditional design) the rotor on the inside. 

Outrunner Rotors

Choosing the rotor materials and grades of the materials will have a large impact on size and weight. Magnetic rotor materials come in all grades depending on the desired output and associated environment. 

Neodymium Iron Boron (NdFeB): NdFeB magnets are the most powerful magnets available today and are widely used in PM motors. They have high energy density and can generate strong magnetic fields with relatively small sizes. Within the spectrum of NdFeB, there are 35+ variants that the magnet material could be made of. Different compositions yield different strengths. 

Samarium Cobalt (SmCo): SmCo magnets are also highly powerful magnets and are used in PM motors that require high-temperature operation. They have a higher Curie temperature than NdFeB magnets and can maintain their magnetic properties at higher temperatures.